If you throw a loyalty trident out and then immediately die before getting it back.
Either of 2 things happen:
If you are far away from where you spawned

• The trident will just be gone.
  If you are close to where you spawned.
• The trident is glitching towards you but you can't catch it.

Also if your inventory is full or you pick up another item in that slot, the trident can't return in the slot you originally threw it from. So to fix the behaviour I suggest the slot the trident is thrown from, to have a placeholder item, such as the fishing rod has. and if you go to far away from the trident, or you die. it can respawn in your inventory without a problem.